1. Field of the Invention
This disclosure relates to a semiconductor device, and more particularly, to a control selection circuit and method which selects a control scheme of a control circuit for controlling a data input/output operation suitable for an operating frequency of a semiconductor device.
2. Description of the Related Art
A semiconductor device such as a semiconductor memory device operates using a control scheme suitable for an operating frequency of an externally applied system clock signal. Such a semiconductor memory device may be used for inputting/outputting data to/from a memory cell of a semiconductor memory device in a computer system. The data input/output speed of the semiconductor memory device is very important in determining the operation speed of the computer system.
FIG. 1 is a block diagram illustrating a semiconductor device 100. Referring to FIG. 1, the semiconductor device 100 includes a control selection circuit 110 and a control circuit 130. The semiconductor device 100 may be, for example, a semiconductor memory device such as a dynamic random access memory (DRAM).
The control circuit 130 controls the semiconductor device 100 to input/output data at a high frequency or a low frequency, in response to a selection signal SEL. The selection signal at SEL is an internal control signal. A reference frequency for generating the high frequency and the low frequency may be, for example, 500 MHz.
The control circuit 130 may include an output data sense amplifier. The output data sense amplifier may be a current sense amplifier. When the semiconductor device 100 operates at the high frequency, the output data sense amplifier of the control circuit 130 may always operate. Thus, a current consumption of the semiconductor device 100 may be large. However, when the semiconductor device 100 operates at the low frequency, the output data sense amplifier of the control circuit 130 may operate only in a valid time interval during which the data is output. As a result the current consumption of the semiconductor device 100 may be small.
The control selection circuit 110 outputs the selection signal SEL for selecting the control scheme of the control circuit 130. The control selection circuit 110 may include a fuse circuit which changes the state of the selection signal SEL depending on whether a fuse is cut or by a mode register set circuit which stores the data for controlling the operation mode of the semiconductor device 100.
Accordingly, the semiconductor device 100 uses only one control scheme in response to the selection signal SEL, and the selection signal SEL is activated in response to the state of the fuse or the state of the mode register, and a specific operating frequency.